Negative permissions, also referred to as "negative ACLs", is a term used for when a system allows access permissions to a folder to be specified as a "deny", rather than an "allow", for either a user or group.

With Files.com, users (excepting site administrators) and groups start without access to any folder. Permissions are used to explicitly allow access for that user or group.

Some systems, such as Active Directory, implement negative permissions. Files.com does not have the ability to synchronize negative permissions from Active Directory.

Instead, permission fences can be used to block inherited permissions to folders and provide similar access rules to those implemented using negative ACLs.